The field of the invention is extended organic paint pigments, especially their use in road marking paints.
Extended pigment compositions may be prepared by mixing pigment with an inert substrate, such as barium sulfate, titanium dioxide, talc, etc. and then modifying the surface properties by treating the extended pigment with a rosin soap. However, such extended, rosinated pigments as are available are lacking in important properties, such as hiding power, light fastness, and scrub resistance; or they have high oil absorbency. The latter property is of particular concern at the present time, as regulations are being imposed to limit the amounts of solvents in paints which are released to the atmosphere as volatile organic pollutants during drying of the paint films. Furthermore, commonly used pigments such as lead chromate are facing increasing use restrictions because of their toxicity.
Persello et al. (1992) U.S. Pat. No. 5,127,952 relates to core/oxide/dye pigmentary colorants; Watanabe et al. (1976) U.S. Pat. No. 3,935,158 and Masuda et al. (1981) U.S. Pat. No. 4,301,050 related road making compositions; Proux (1962) U.S. Pat. No. 3,051,590, Pojurowski et al. (1963) U.S. Pat. No. 3,092,507 and Flasch (1961) U.S. Pat. No 3,002,846 relate to uses of coating compositions involving lithopone.